Clustering and α -capture reaction rate from ab initio symmetry-adapted descriptions of Ne20

Efficacy of the symmetry-adapted basis for ab initio nucleon-nucleus interactions for light- and intermediate-mass nuclei

“…In this paper, we have studied the efficacy of the new ab initio SA-RGM approach that combines the SA-NCSM and RGM frameworks. We have discussed nucleonnucleus interactions and the use of the SA framework for 4 He and 16 O targets, as well as the intermediatemass 20 Ne and 23 Mg targets feasible in the SA-NCSM. We have shown that the SU(3) selection of the model space has almost negligible effect on the SA-RGM norm and particle-rank one potential kernels that provide the input to calculations of phase shifts and cross sections.…”

“…We find that the number of the 23 Mg+N SA-RGM states continues to scale polynomially with increasing N max for each ε and largely decreases for higher ε reduction cutoffs. We note that the ε = 10 −6 cutoff uses the 23 Mg basis states with a probability greater that 10 −6 and results in no reduction. In the SA-RGM calculations, the ε cutoff for the SA selection is decreased until convergence of results is achieved.…”

“…Furthermore, there is a large reduction in the number of SU(3) basis states needed for the target wave functions, as one eliminates negligible contributions identified in the target eigenfunctions. Namely, for the illustrative example of the 23 Mg target (Fig. 6), we show the number of the SA-RGM channels after retaining basis states that contribute with a probability amplitude (C ω1κ1L1S1 b1 ) 2 [see Eq.…”

“…The access to higher-lying shells makes the SA basis suitable for describing nuclear reactions [9], the processes that are typically studied in experiments and govern stellar evolution. Remarkable progress has been made in firstprinciple descriptions to scattering and nuclear reactions for light nuclei (for an overview, see [10,11]), including studies of elastic scattering [12][13][14][15][16][17][18], photoabsorption [19], transfer [20] and capture reactions [21], α widths [22,23] and resonant states [24], as well as thermonuclear fusion [25]. In this paper, we show that expanding the reach of ab initio reactions to deformed and heavier targets is now feasible with the SA basis.…”

$α$-cluster structures above double shell closures via double-folding potentials from chiral effective field theory

“…They are adopted in literature to study α-cluster structures across the nuclide chart. In principle, some more sophisticated microscopic models could also be used to study α-cluster structures above double shell closures, such as antisymmetrized molecular dynamics (AMD) [28][29][30], quantum Monte Carlo method (QMC) [31], lattice effective field theory [32], configuration interaction method [33], symmetry-adapted no-core shell model [34], etc. However, due to heavy computational load, their applications are mainly restricted to light nuclei.…”